1. Field of the Invention
The present invention relates to an assembly for packaging of products for lightening or bleaching the hair and to a method for lightening or bleaching the hair using such an assembly. In the present description and in the claims the terms "lightening" and "bleaching" will be used interchangeably, the two concepts differing only in the extent of the change of colour and therefore corresponding to the same action carried out to different degrees.
2. Description of the Prior Art
At present, in order to lighten or bleach the hair, a paste is prepared which is obtained by mixing, just before use, a bleaching powder containing a peroxygen salt and a developer, in most cases based on aqueous hydrogen peroxide, the mixture obtained is applied, either over the whole of the hair or on tufts, for a specific period of time, then, to finish, the hair is washed with water and dried. Unfortunately, during the mixing of the bleaching powder and the developer, a cloud of bleaching powder is formed which irritates the nasal mucosa and which releases an unpleasant smell.
In order to overcome this drawback, it has been proposed to store the bleaching powder in a plastic sachet and to mix the bleaching powder and the developer, inside the plastic sachet, by manual heading: a method of this type is described in U.S. Pat. No. 4,116,365 and in U.S. Pat. No. 4,506,783. However, with the method described in the abovementioned patents it is not possible to eliminate all the risks of a cloud of bleaching powder being released into the atmosphere, and it additionally involves relatively bulky packaging assemblies.